* java.util.LinkedHashSet}. Generally speaking, this class reduces object allocation and memory
 * consumption at the price of moderately increased constant factors of CPU. Only use this class
 * when there is a specific reason to prioritize memory over CPU.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible // not worth using in GWT for now

 * java.util.LinkedHashSet}. Generally speaking, this class reduces object allocation and memory
 * consumption at the price of moderately increased constant factors of CPU. Only use this class
 * when there is a specific reason to prioritize memory over CPU.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible // not worth using in GWT for now

        assertTrue(customException.getCause() instanceof FessSystemException);

        // Test with Error (not Exception)
        Throwable errorCause = new OutOfMemoryError("Out of memory");
        GsaConfigException errorException = new GsaConfigException("GSA memory error", errorCause);
        assertNotNull(errorException);
        assertTrue(errorException.getCause() instanceof OutOfMemoryError);
    }

   * response body. Call `body.source().request(1024 * 1024)` to block until either that's done, or
   * 1 MiB of response data is loaded into memory. (You could use any size here, though large values
   * risk exhausting memory.)
   *
   * This returns an empty value if the trailers are available, but have no data.
   *

/**
 * {@linkplain CacheBuilder Discouraged} (in favor of <a
 * href="https://github.com/ben-manes/caffeine/wiki">Caffeine</a>) caching utilities.
 *
 * <p>The core interface used to represent caches is {@link Cache}. In-memory caches can be
 * configured and created using {@link CacheBuilder}, with cache entries being loaded by {@link
 * CacheLoader}. Statistics about cache performance are exposed using {@link CacheStats}.
 *

- Fluent API for building HTTP requests (GET, POST, PUT, DELETE, HEAD, OPTIONS, CONNECT, TRACE)
- Support for query parameters, headers, body (String or stream), compression, SSL configuration, proxies, and timeouts
- Automatic in-memory or on-disk caching of request/response bodies
- Synchronous and asynchronous (callback) execution
- Minimal dependencies (only Apache Commons IO)

## Installation

### Maven

    }

    private void appendJvmStats(final StringBuilder buf) {
        buf.append("\"jvm\":{");
        final JvmStats jvmStats = JvmStats.jvmStats();
        final Mem mem = jvmStats.getMem();
        buf.append("\"memory\":{");
        buf.append("\"heap\":{");
        append(buf, "used", () -> mem.getHeapUsed().getBytes()).append(',');
        append(buf, "committed", () -> mem.getHeapCommitted().getBytes()).append(',');

        // Test that constructor accepts Error as cause (verifies Throwable parameter change)
        String message = "SSO process failed due to OutOfMemoryError";
        OutOfMemoryError error = new OutOfMemoryError("Insufficient memory for SSO processing");
        SsoProcessException exception = new SsoProcessException(message, error);

        assertEquals(message, exception.getMessage());
        assertNotNull(exception.getCause());

    }

    /**
     * Returns a {@link ByteBuffer} that maps the file channel to memory.
     *
     * @param channel
     *            The file channel. Must not be {@literal null}.
     * @param mode
     *            The mode. Must not be {@literal null}.
     * @return A {@link ByteBuffer} that maps the file channel to memory.
     */
    public static ByteBuffer map(final FileChannel channel, final MapMode mode) {

        // Test Error with abort flag
        String url = "http://example.com/critical-resource";
        String message = "Critical memory error during crawling";
        OutOfMemoryError error = new OutOfMemoryError("Cannot allocate memory");

        DataStoreCrawlingException exception = new DataStoreCrawlingException(url, message, error, true);

        assertEquals(url, exception.getUrl());